Process for improving wool



Patented July 13, 1937 UNITED STATES PATENT OFFICE PROCESS FOR IMPROVING WOOL Alexander Nathansohn, Berlin-Wilmersdorf, Germany, assignor to the firm Dentsche Kunstseiden-Studiengeselischaft m. b. 11., Berlin, Germany No Drawing. application September 26, 1933, Se-

rial No. 691,093. In Germany November 4, 1930 2 Claims.

' obtainable in other ways.

The process consists in treating wool with acid derivatives of organic acidradicals with at the most, eight carbon atoms, whilst practically no water, may be added; although it does no harm in the small amounts in which it is introduced, for example, by the customary moisture of the wool, or of the chemicals use Fundamentally every kind of wool ofany degree of operation may be subjected successfully to the process in practically dry condition, but the washing or the extraction of the wool grease by organic solvents must precede the improvm ing process.

is subjected to the process under the same conditions. It is, however, necessary to observe that wool, not only from a colloidal chemical point of view, but also as regards its organized structure,

is a'complicated body of which the properties so may vary from case to casei according to quality,

preliminary treatment and duration of storing. For these reasons, it has been found even in in the oldest known improving processes-viz in wool washing, that according to the nature of the- 8 initial material a similar procedure may lead to different results, which are frequently satisfactory, frequently unsatisfactory, so that it is often necessary to adapt the method of rryingout the process to the properties of the materiaL- In 40 complicated cases of the improving process, as

when chlorinating, it is well 'known that frequently when using the same methods, as otherwise produce satisfactory results, the wool deteriorates.

woolen textiles are met with, to which softness and gloss cannot be imparted by any of the current methods of operation. Thus the result. of

the process according to theinventlon' is not al- 50 way! the same in connection with similar mateaciddyedwoohandinthiscasethemethod of' rials when carrying out the processin the same way: for example, as will be more fully explained, the effects in thecase of raw wool are somewhat different than in the case of dyed, particularly It is generally well known that frequently carrying out the process is not entirely the same.

In general, however, it may be said that the re sult of the process is better the more rapidly it follows the last'improvingprocess carried out, for example, the washing or dyeing. It has also been found of advantage to treat wool which,

during washing, has not been subjected to too strong an alkaline treatment. The washing must therefore be effected in as moderate a manner as possible.

Consequently, it is also necessary with this new process to test the suitability of every material and the intensity of treatment to be employed from case to case. Further it is of importance in view of the apparently purely colloidal chemical character of the process to subject the material to the treatment in the cleanest condition possible.

As regards the result of the process according to the invention in connection with-various materials, it can generally be ascertained in the case of raw wool that when the process is carried out correctly, the colour is. whiter so that in certain cases even the bleaching can be omitted entirely. Also, in the case of felty wool, felting is reduced'so that the wool article can be treated more easily in the spinning and combing works. Further the material also becomes more elastic; a tuft of treated raw wool can be compressed more easily and again expands when the pressure is removed; the grip of the material becomes softer.

Also, in the case of undyed cardings, a substantia. brightening can be obtained. Raw wool yarn mostly becomes winter and softer and in many qualities there occurs a loosening of the thread which is especially of importance when treating the yarn for knitted articles. In the case of raw and bleached woven goods, a greater softness can also be obtained.

Raw and bleached woollen goods of the character described, which have been subjected to the process, behave more favourably during dyeing;

By the same treatment there are obtained more luminous and fuller colour tones.

when the process is applied to dyed, particularly to acid dyed woollen goods, it is possible in the first instance to obtain a silky gloss of the material.

In the case of cardinga yarns knitted and woven goods, then frequently also occurs a very considerable reduction in shrinkage during wash- For carrying out the process, there are partlcularly suitable acid derivatives of fatty acid radicals of not too high a carbon number; the limit is practically 8 carbon atoms and preferably up to 5 carbon atoms are employed. Formic acid has the best effect. Favorable also are acetic acid and acetic acid anhydrides. Chlorinated acetic acids and their anhydrides, for example, monoor trichloracetic acid, and also propionic acid anhydride have a still better effect. In practice, there is mostly used formic acid or chlorinated acetic acid. which has a somewhat weaker action than formic acid but has the advantage of being odourless, so that aeration or neutralization of the material is not necessary. When using acetic acid anhydride, the reagent is used at most in 15 percent solution in an indifferent organic solvent. There may also'be used various of the said reagent groups and reagents in combination with one another.

when carrying out the process according to the invention, the following is to be observed:

The maximum eflect is not obtained by the most powerful action of the acid possible, but on the contrary, the action and best result is 'ob-' tained within certain limits. If, however, by prolonging the time, by increasing the concentration or the temperature, the acid action is increased, the effect is again lost, the material is not improved, but on the contrary under certain conditions to be more clearly set out, the initial material is deteriorated.

The circumstance that wools of a similar nature but of different prediminary treatment may act very differently in all improving processes therefore makes necessary in each 0886 to ;ample, by suction, the remainder by aeration,

'whilst under the circumstances, for example,

certain the exact conditions under which the effect is produced. The steps thus necessary differentiate the new process substantially from the process in which wool was hi'herto acetylized in order to render it non-dyeing. and to use it as immunized yarn. In this previously known method of treatment it is necessary by the use of strong media, for example acetyl chloride with a powerful catalyst such as sulphuric acid, to carry out the acetylizing to a far reaching extent to eliminate the capacity to dyeing. Materials treated in this manner, however, no longer exhibit the eflects obtainable by the new process.

An essential feature of the new process consists in carrying out the treatment with the chemicals in question only to such an extent that the dyeing property of the wool is not appreciably affected in respect to whether the wool is to be dyed subsequently or not. The avoidance of the rendering immune is therefore'a characteristic feature of the presentprocess.

In accordance with the invention, a "moderate esteriflcation is an esteriflcation as a result of which the physical chemical property of the material, particularly its dyeing property in the main does not practically suffer any change.

For carrying out the process, it is essential for the process'to be carried out only in the absence of appreciable quantities of water. It cannot be carried out for instance when using dilute solutions of acetic or formic acid by which under circumstances, there can be obtained a certain improvement in the apparatus but not in the characteristic eifects of the process according to the invention, and particularly an improvement in the quality of raw wool which resides in the greater softness, in the brighter colour and in the increase in its spinning property and not in the properties which the new process is adapted to obtain in the case of dyed yarns and the reaosacve I production of the effect of chlorinating: viz., the

whereby, asstated above, the desired eifect would again be liable to be destroyed. As liquid reaction medium there are therefore preferably used solutions of the reagents in question, in organic solvents as for example solutions of 40% glacial acetic acid in benzene solutions of 10% acetic acid anhydride in carbontetrachloride or saturated solutions of formic acid, 0.2% solutions of tetrachlor acetic acid or monochlor acetic acid, 0.4% benzoic acid and so forth in one of the said solvents, whilst there is preferably used a floating ,ratio between 1:10 and 1:30. It has been found of advantage to avoid entirely oxygencontaining solvents such as alcohol, acetone and so forth or to add them at least in small quantities to the solvent free from oxygen.

When using such solutions, the material is soaked therewith preferably at temperatures between 20 and 40 C., in the case of undyed goods as a rule between 1 and 4 hours, for dyed goods between 4 and 6 hours according to the concentration of the reagent, the temperature and the reaction capacity of the material. Aftersoaking, the main mass of solvent is removed, for exwhen using formic acid or acetic acid anhydride, the acid excess adhering firmly to the material is neutralized by the addition of small quantities of ammonia to the circulating air.

The process may also be carried out by allowing the reagents to act ingaseous form on the material, for example while heating to 35 degrees C. or above, such as treatment for an hour in air which at about 50 C. has'been saturated with formic acid vapours. Ithas been found of advantage to charge this circulating air also with the vapour of an organic solvent such as benzene and'so forth, in addition to that of the man. The action occurs, be it after days, even when the wool is stored at ordinary temperature in an atmosphere containing small hardly noticeable quantities of formic acid vapours.

It is also possible to make a combination of these principles by soaking the material with a solution of the active chemicals in an organic solvent, which preferably, has a lower boiling point than the chemicals in question. By squeezing or sucking the main portion of the solution from the material and removing the remainder of the solvent by aeration, the reagent having the higher boiling point, remains wholly or partly in .the material. If the material is ,then exposed to temperature above the evaporating temperature of the sol vent employed, then, particularly when using temperatures above C.-, in practice about active results can under the circumstances, be obtained particularly rapidly, especially gloss effects on dyed piece goods. This process-is particularly used when the new effect is to be combined with other effects which are obtained by higher temperatures, for example, the increase of the waterproofness of the goods by the action of anhydrides of higher fatty acids.

Examples I (In all the examples there was used a floating ratio of 1:20).

,Acid dyed carded yarn, which comes freshly from treatment, is treated tor six hours at 40 C. with a solution of 39% glacial acetic acid in benzene. After this period of time, the solution is drawn off and the remainder removed by aeration. The material has become more glossy and during ordinary washing shrinks less than the initial material.

Raw carded yarn, which has been carefully freed, from grease by suitable washing, is treated for two hours in a solution of 1.4% formic acid in benzene. The removal of the solution is effected as in Examples 1 and H. The material has become considerably brighter, of better appearance, shrinks less on washing, also has a longer drawing and is of considerably higher value than the initial material.

Raw carded yarn is treated as in Example 111, but with a. saturated solution of formic acid in carbon tetrachloride. The result is the same.

As in Example Hi. but with the use of a solution of 10% acetic acid anliydride in henaine. The result is the same as in Example ill.

I As in Example m, but with the use oil a solution of 0.2% trichlor acetic acid in lienziiie. The

result is the same as in Example III, but extends mainly to the improvement 01' the dye, whilst the material does not become looser in dimensions as in the process in Example III.

' VII 'Dyed carded yarn is exposed for six hours at a temperature of 50 acid vapour whereupon the odour adhering to the wool is removed by powerful aeration or by neutralization by means of ammonia. The resuit is exactly the same as in Example II.

' VIII Acid dyed cloth is soaked in a solution of 0.5% acetic acid anhydride in benzine, and hav ing a boiling point of 80-90 0., squeezed and freed from excess benzine by aeration. The cloth is then exposed for minutes to a temperature of 135--1 l5 C. whilst it improves considerably in gloss by this process. 1

I claim:

C. to the action of iornnic 1. The process of refining wool to produce soft ness and brightness and improve its spinning property without essential change of the dyeing capabilities thereof, which comprises treating the clean dry wool after grease extraction with formic acid vapor diluted with. air in the substantial absence of water at a temperature between room temperature and 50. degrees (2.,

whereby to effect a moderate esterification, and 1 terminating the treatment prior to any substantial change in the dyeing property of the wool.

2. The process of refining wool to produce softness and brightness and improve its spinning property without essential change of the dyeing capabilities thereof, which comprises the steps oil immersing the clean dry wool after grease extraction in a. solution of formic acid in a vole. tile organic solvent substantially free from water and other oxygen-containing compounds at a temperature approximating degrees C. for a time substantially between 1 hour and 6 hours, whereby to effect a moderate'esterifieation, and withdrawing and separating the wool from the solution prior to any substantialchangc in the dyeing property of the wool.

ALEXANDER NATHANSOHN. 

